Chris H. Q. Ding Ding Zhou Xiaofeng He Hongyuan Zha <i>R</i><sub>1</sub>-PCA: rotational invariant <i>L</i><sub>1</sub>-norm principal component analysis for robust subspace factorization. 281-288 2006 conf/icml/2006 ICML http://doi.acm.org/10.1145/1143844.1143880 db/conf/icml/icml2006.html#DingZHZ06